Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA.
Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA.
J Cardiovasc Electrophysiol. 2022 May;33(5):975-981. doi: 10.1111/jce.15410. Epub 2022 Mar 5.
Intramural ventricular arrhythmias (VAs) can originate in patients with or without structural heart disease. Electrogram (EGM) recordings from intramural sources of VA have not been described thoroughly.
We hypothesized that the presence of scar may be linked to the site of origin (SOO) of focal, intramural VAs.
In a series of 21 patients (age: 55 ± 11 years, 12 women, mean ejection fraction 43 ± 14%) in whom the SOO of intramural VAs was identified, we analyzed bipolar EGM characteristics at the SOO and compared the findings with the endocardial breakout site. The patients were from a pool of 86 patients with intramural VAs referred for ablation.
In 16/21 patients intramural scarring was detected by cardiac magnetic resonance (CMR) imaging In patients in whom the intramural SOO was reached, intramural bipolar EGMs showed a lower voltage and had broader EGMs compared to the endocardial breakout sites (0.97 ± 0.56 vs. 2.28 ± 0.15 mV, p = .001; and 122.3 ± 31.6 vs. 96.5 ± 26.3 ms, p < .01). All intramural sampled sites at the SOO had either low voltage or broad abnormal EGMs. The activation time was significantly earlier at the intramural SOO than at breakout sites (-36.2 ± 11.8 vs. -23.2 ± 9.1 ms, p < .0001).
Sites of origin of intramural VAs with scar by CMR display EGM characteristics of scarring, supporting that scar tissue localizes to the SOO of intramural outflow tract arrhythmias in some patients. Scarring identified by CMR may be helpful in planning ablation procedures in patients with suspected intramural VAs.
心室内室性心律失常（VA）可起源于有或无结构性心脏病的患者。VA 心室内起源的电图（EGM）记录尚未得到充分描述。
我们假设疤痕的存在可能与局灶性、心室内 VA 的起源部位（SOO）有关。
在一系列 21 名患者（年龄：55±11 岁，12 名女性，平均射血分数 43±14%）中，心室内 VA 的 SOO 被确定，我们分析了 SOO 处的双极 EGM 特征，并将结果与心内膜突破部位进行比较。这些患者来自 86 名接受消融治疗的心室内 VA 患者的一组。
在 21 名患者中的 16 名患者中，心脏磁共振（CMR）成像检测到心室内疤痕。在心室内 SOO 可到达的患者中，与心内膜突破部位相比，心室内双极 EGM 显示出较低的电压和较宽的 EGM（0.97±0.56 与 2.28±0.15 mV，p=0.001；122.3±31.6 与 96.5±26.3 ms，p<0.01）。SOO 处所有取样的心室内部位均有低电压或异常宽的 EGM。心室内 SOO 的激活时间明显早于心内膜突破部位（-36.2±11.8 与-23.2±9.1 ms，p<0.0001）。
CMR 检测到有疤痕的心室内 VA 的起源部位显示出疤痕的 EGM 特征，支持在某些患者中，疤痕组织定位于心室内流出道心律失常的 SOO。CMR 识别的疤痕可能有助于计划疑似心室内 VA 患者的消融程序。
